Identifying novel microhaplotypes for ancestry inference.

The use of DNA to determine the ancestry of an individual is becoming more and more important in the areas of forensics. Kidd et al. (Forensic Sci Int Genet 12:215-224, 2014) have been the first to identify and catalog haplotypes, termed as minihaplotypes (1-10-kilobase spans) and microhaplotypes (≤ 200 bp), with potential use in forensic analysis. In the present study, we selected 10 short ancestry informative microhaplotypes by calculating the informativeness (In) according to Rosenberg et al. (Am J Hum Genet 73(6):1402-1422, 2003). In total, 2504 individuals from 26 populations in 1000 Genomes Project database Phase 3 were enrolled. Among the studied microhaplotypes, eight of them are comprised of 3 SNPs while two microhaplotypes are made up of 4 SNPs. The size (molecular extent) range of 10 microhaplotypes is 5 to 48 bp with an average of 31.4 bp. The heterozygosity value ranges from 0.2235 to 0.8958 with an average of 0.6593. The average power of discrimination (PD) values is 0.7944 and ranges from 0.3786 to 0.9242. Analyses of this dataset provided clear differentiation of the populations from the Africa, East Asia, South Asia, and Europe biogeographic regions. However, individuals from American ancestry were not well separated. To conclude, our results revealed the significance of using microhaplotypes as an ancestry informative marker. The present panel could offer a valid complementary tool in forensic applications.